Method and apparatus of establishing a region to be made amorphous

Abstract

In a method of accurately determining an area that has been changed to an amorphous state which uses a computer simulation of a semiconductor manufacturing process, the impurity concentration at the crystalline-amorphous boundary is taken as the parameter C.The value obtained by dividing the implanted ion concentration obtained by means of an ion implantation simulator by the parameter Ca is defined as the amorphous conversion ratio parameter, and a region in which this amorphous conversion ratio parameter is 1 or greater is taken to be an area that is converted to an amorphous state.

What is claimed is:  
     
       1. A method of establishing, by utilizing a computer simulation of a semiconductor device manufacturing process, a region that has become amorphous, said method comprising the steps of: 
       determining an impurity concentration at an interface formed between a crystal and an amorphous region, as a parameter Cα;  
       determining an ion implantation concentration of an ion of said impurity concentration which is implanted thereinto by utilizing said computer simulation;  
       defining an amorphous conversion ratio parameter Rα as said ion implantation concentration divided by said parameter Cα; and  
       locating said amorphous region by determining said region that has been converted to an amorphous state at the time of ion implantation, as a region in which said amorphous conversion ratio parameter Rα is at least 1.  
     
     
       2. A method of establishing a region that has become amorphous according to claim  1 , comprising a plurality of conditions for said ion implantation, and further comprising the steps of: 
       measuring the values of impurity concentrations at said interface formed between said crystal and said amorphous regions, with respect to specific conditions of said plurality of conditions, and  
       using values predicted by performing at least one of an interpolation and an extrapolation of said measured values as said parameter Cα with respect to each condition.  
     
     
       3. A method of establishing a region that has become amorphous according to claim  2 , further comprising the steps of: 
       measuring previously for each one of said plurality of conditions for said ion implantation, the values of impurity concentration at said interface formed between said crystal and amorphous regions, with respect to each one of a plurality of specific conditions thereof, and  
       storing each one of said values of impurity concentration thereat, thus measured, in a suitable memory device; and further wherein  
       determining a region that has become amorphous, by using a parameter Cα with respect to the specific condition, calculated by using a value predicted by performing said at least one of an interpolation and an extrapolation of a plurality of said measured values stored in said memory device, and each of which having a condition being closer to said condition.  
     
     
       4. A method of establishing a region that has become amorphous according to claim  1 , wherein a plurality of ion implantations are performed further comprising the steps of: 
       calculating a sum of said amorphous conversion ratio parameters with respect to each ion implantation, and  
       determining a region in which said sum is at least 1 is determined as a region that has been converted to an amorphous state at the time of ion implantation.  
     
     
       5. A method for establishing a region that has become amorphous as recited in claim  4 , wherein 
       said plurality of ion implantations comprise different types of impurities.  
     
     
       6. A method for establishing a region that has become amorphous as recited in claim  1 , further comprising 
       utilizes a computer memory and a look up table for determining Cα.  
     
     
       7. An apparatus, for establishing a region that has become amorphous by utilizing a computer simulation device of a semiconductor device manufacturing process, said apparatus comprising: 
       a device for measuring an impurity concentration at an interface formed between a crystal region and an amorphous region, and determining said measured impurity concentration thereat as a parameter Cα;  
       a device for simulating an ion implantation concentration of an ion of said impurity concentration which is implanted thereinto by utilizing a computer;  
       a device for calculating a value of ratio obtained from said ion implantation concentration divided by said parameter Cα, and determining said ratio as an amorphous conversion ratio parameter Rα; and  
       a device for locating said amorphous region by determining a region in which said amorphous conversion ratio parameter Rα thereof is at least 1, as a region that has been converted to an amorphous state at the time of ion implantation amorphous state at the time of ion implantation.  
     
     
       8. An apparatus for establishing a region that has become amorphous according to claim  7 , wherein 
       said apparatus is further provided with a memory device for storing a plurality of impurity concentrations at an interface formed between a crystal region and an amorphous region, measured at each one of a plurality of specific conditions among a plurality of conditions.  
     
     
       9. An apparatus for establishing a region that has become amorphous as recited in claim  7 , wherein 
       said Cα determination utilizes a computer memory and a look up table.